<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<form onsubmit="testform()" novalidate="true">  
            <label for="email"> 邮箱：</label>  
            <input type="email" id="email" name="email"/>  
            <input type="submit" value="提交">  
        </form>  
	</body>
	
	<script>
	    function testform(){  
	        var email=document.getElementById('email');  
	        if(email.value==''){  
	            alert('请输入email！');  
	            return false;  
	        }else if(!email.checkValidity()){  
	            alert('email的格式不正确！');  
	            return false;  
	        }  
	    }  
    </script>  
</html>
